Tilemap collisions?

There is a number of expressions you can use to convert from layout coordinates to tilemap x,y:

PositionToTileX(x)

PositionToTileY(y)

Convert an X or Y layout co-ordinate in to the corresponding tile number in the tilemap. For example, this can be used to get the tile position under the mouse.

SnapX(x)

SnapY(y)

Snap an X or Y layout co-ordinate to the nearest tile. This also returns a layout co-ordinate, but aligned to the nearest tile in the tilemap.

TileAt(x, y)

Return the tile ID at a position in the tilemap. Note the position is given in tiles, not layout co-ordinates. If the tile at the given position is empty (has been erased), the expression returns -1.

TileToPositionX(x)

TileToPositionY(y)

Convert a tile position to layout co-ordinates. For example, this can be used to position a Sprite object on top of a given tile.

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So you can get tile number that player is on using this formula:

tilesMap.TileAt(tilesMap.PositionToTileX(player.X), tilesMap.PositionToTileY(player.Y))

You can check 4 points at some offset from the player to prevent it from stepping into water etc.

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Creating a separate invisible solid tilemap for collision detection is actually a very good and popular solution. It will not make your project file any larger, because you only need one tile (just a black square).

You can auto-generate this collision tilemap based on tiles on your main tilemap. Just loop through all x,y tiles on your main tilemap and set or erase corresponding tiles on the collision tilemap.

When your player is in "walking" mode, erase entire collision tilemap and then set tiles with water, trees, mountains etc. When your player is in "boat" mode, set tiles for the entire collision tilemap, and then erase water tiles.

The top method is perfect for what I'm doing. After testing it, it's working perfectly well. I was doing it ALMOST correctly but didn't realize I had to do the "tilesmap.PositionToTile.X(player.X)" part. I thought it was a bit more simple than that lol.

However, one last question about this, if I need to check multiple tiles, (for example, all "mountain" tiles of different colors), and they start at 60, I know the OR expression is a pipe (|).

So I have this

tilesMap.TileAt(tilesMap.PositionToTileX(player.X), tilesMap.PositionToTileY(player.Y)) = 60|61|62|63|64

HOWEVER it now only does it with tile 1 (my water tile) which isn't even in the equation. Is there another way of doing this without it having to be copied and pasted multiple times?

HINT: I have put spaces between the numbers and pipes, putting the numbers in quotes, and using parentheses as well. Example: 60 | 61 | 62 etc.; "60"|"61"|"62" etc., (60)|(61)|(62) etc. Is there something wrong with this particular plugin or am I just doing something wrong?

EDIT: The reason I need "OR" to be involved instead of just doing a "greater or equal" with a "less or equal" duplicate is because not all of my solid objects are in a row, so it would take even more code. I'm all about efficiency (which is why I need that way you first described to handle everything).

Then why would they have the operators like that in the manual if we weren't able to use them in conditions?

https://www.scirra.com/manual/78/expressions

Thanks, R0J0hound

Is there a way you could give me an example in the file I provided up top? That is, the "Sprite.x=22 | sprite.x=33 | sprite.x=66" part.

Also, I'm not exactly sure how to pull off a function like this.

You can use "Between values" condition:

tilesMap.TileAt(tilesMap.PositionToTileX(player.X), tilesMap.PositionToTileY(player.Y)) Between 60 and 64

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You can use the "|" operator like this:

Set variable tempTile=tilesMap.TileAt(tilesMap.PositionToTileX(player.X), tilesMap.PositionToTileY(player.Y))
System compare two values: (tempTile=60 | tempTile=61 | tempTile=62 | tempTile=63 | tempTile=64) EQUALS 1

You could use helper functions that makes it explicit what each condition does.

IsTileWater(x,y)

IsTileMountain(x,y)

etc

You could then also create another function that re-use those.

IsTileObstacle(x,y)

This function could then allow you to alter the way your sprite can move. Like this. Please forgive my awesome artistic talent. :)